METHOD FOR DECREASING DEW POINT OF HEATING FURNACE

摘要

PURPOSE:To reduce the time required for decreasing the dew point of a heating furnace and to improve the operating efficiency thereof by heating the inside of the furnace while injecting an inert gas or reducing gas of a low dew point into the spacing between the outside wall of the furnace body and refractories of the heating furnace. CONSTITUTION:The inside of the heating furnace A for heating treatment of a material C to be heated conveyed by means of rollers B is heated up while the inert gas or reducing gas of <=-40 deg.C dew point is introduced from a gas feed main pipe 4 through a branch pipe 5 and a gas feed hole 6 into the spacing 3 between the outside wall 2 of the body of the furnace A and the retractories 1 lined on the inside thereof and is discharged from a discharge hole 9 to a discharge pipe 11 prior to the operation of the above-mentioned furnace. The gaseous N2 having -78 deg.C dew point is suitable as the above-mentioned inert gas and the gaseous Ax (N2+H2) or the like having -70 deg.C dew point is adequate as the reducing gas. The gas is preferably preheated to about 250-300 deg.C to maintain the pressure in the spacing 3 slightly higher than the pressure in the furnace. The moisture of the refractories 1 is thereby absorbed and the decrease of the dew point in the furnace is accelerated.